This invention relates to an air removal device which is used to remove bubbles mixed in ink flowing through an ink passage in an ink supply mechanism mounted on an ink-jet printer, the ink supply mechanism provided with the air removal device, and the ink-jet printer.
A conventionally known air removal device for ink supply mechanism, for example, includes an ink chamber in an ink passage from an ink supply source to a recording head. When bubbles (air) mixed in ink flowing through the ink passage are collected to the upper part of the ink chamber, the collected air is discharged to the outside via an air discharge passage.
In the vicinity of an entrance to the air discharge passage, an air permeable membrane is provided which passes air but not ink. When a positive pressure to the ink chamber side or a negative pressure to the air discharge passage side is applied by a pump, the air collected in the upper part of the ink chamber passes through the air permeable membrane to flow from the ink chamber to the air discharge passage. When ink flows into the ink chamber from upstream of the ink passage as the air in the upper part of the ink chamber is discharged, ink and the air permeable membrane are brought into contact with each other in the end. As a result, there is no more permeation of air from the ink chamber to the air discharge passage. Thus, removal of air is complete.